Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall in September
- Average snowfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
The onset of September aligns with a soft reduction in the average high-temperature, gently falling from a moderately hot 80.6°F (27°C) in August to a still warm 73.4°F (23°C). Willow Brook cools down to an average low-temperature of 54.1°F (12.3°C) throughout the month of September.Humidity
In September, the average relative humidity is 79%.Rainfall
The month with the least rainfall is September, when the rain falls for 10.4 days and typically collects 0.63" (16mm) of precipitation.Snowfall
June through September are months without snowfall.Daylight
In Willow Brook, the average length of the day in September is 12h and 28min.On the first day of September, sunrise is at 6:24 am and sunset at 7:29 pm. On the last day of the month, sunrise is at 6:53 am and sunset at 6:40 pm EDT.
Sunshine
The average sunshine in September is 8.7h.UV index
The average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a medium vulnerability from unprotected exposure to Sun's UV rays for the average person.Note: A maximum high daily UV index of 4 during September translates into the following directions:
Prioritize safety - Recommendations to avert sunburn are shared. When the Sun is at its strongest around midday, find shade and limit exposure. Counter UV radiation's ill effects with clothing designed for sun safety and UV-resistant eyewear.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are the temperatures in September?
What is the average humidity in September in Willow Brook?
What is the driest month?
How many days does it rain in September?
When it does not snow?
Does it snow in September?
What is the average length of the day in September?
When is the sunrise / sunset in September?
How many hours of sunshine does Willow Brook have in September?
What is the UV index reading in September?
Average temperature in September
Willow Brook, NJ
- Average high temperature in September: 73.4°F
The warmest month (with the highest average high temperature) is July (82.9°F).
The month with the lowest average high temperature is January (33.3°F).
- Average low temperature in September: 54.1°F
The month with the highest average low temperature is July (62.1°F).
The coldest month (with the lowest average low temperature) is January (20.5°F).
Average pressure in September
Willow Brook, NJ
- Average pressure in September: 30.06"Hg
The month with the highest atmospheric pressure is November (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in September
Willow Brook, NJ
- Average wind speed in September: 5.2mph
The windiest months (with the highest average wind speed) are January and March (7.5mph).
The calmest month (with the lowest average wind speed) is August (4.7mph).
Average humidity in September
Willow Brook, NJ
- Average humidity in September: 79%
The months with the highest relative humidity are February, October and December (81%).
The month with the lowest relative humidity is April (76%).
Average rainfall in September
Willow Brook, NJ
- Average rainfall in September: 0.63"
The wettest month (with the highest rainfall) is July (1.77").
The driest month (with the least rainfall) is September (0.63").
Average rainfall days in September
Willow Brook, NJ
- Average rainfall days in September: 10.4 days
The month with the highest number of rainy days is July (15.8 days).
The month with the least rainy days is January (5.8 days).
Average snowfall in September
Willow Brook, NJ
- Average snowfall in September: 0"
The month with the highest snowfall is March (1.69").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Willow Brook, NJ
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (7.3 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Willow Brook, NJ
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).
- Average sunshine in September: 8h and 4min
The month with the most sunshine is July (Average sunshine: 10h and 18min).
The month with the least sunshine is February (Average sunshine: 4h and 24min).
Average sunshine days in September
Willow Brook, NJ
- Average sunshine days in September: 16.9 days
The months with the most sunshine days are January and November (20.4 days).
The month with the least sunshine days is June (12.5 days).
Average UV index in September
Willow Brook, NJ
- Average UV index in September: 4
The month with the highest UV index is June (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 2).
Average cloud cover in September
Willow Brook, NJ
- Average cloud cover in September: 40
The month with the most cloud cover is February (Cloud cover 51).
The months with the least cloud cover are July and August (Cloud cover 35).
Average visibility in September
Willow Brook, NJ
- Average visibility in September: 5mi
The months with the highest visibility are April and November (6mi).
The months with the lowest visibility are January, February, March, May, June, July, August, September, October and December (5mi).
Willow Brook, New Jersey, USA
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